The present inventive concept relates to semiconductor memory devices, and more particularly, to memory systems including nonvolatile memory and to erase methods of memory systems including nonvolatile memory.
Semiconductor memory devices are generally classified as either volatile semiconductor memory devices or nonvolatile semiconductor memory devices. Volatile semiconductor memory devices, which generally exhibit high read/write speeds, are characterized by the loss stored data when their power supplies are interrupted. In contrast, nonvolatile semiconductor memory device retain their stored data even when their power supplies are interrupted. Thus, nonvolatile memory devices are used when stored contents are to be preserved regardless of whether or not power is supplied.
A popular example of a nonvolatile memory device is a flash memory device, which is widely used as the voice and image data storage media of information devices such as computers, cellular phone, PDA's, digital cameras, camcorder, a voice recorder, a MP3 player, a personal portable terminal, a handheld PC's, game machines, fax scanners, and printers.
A charge trap type of flash memory device, for example, may include a cell string formed in a direction perpendicular to a substrate to form a three-dimensional NAND flash memory. However, the three-dimensional NAND flash memory may exhibit relatively low erase speeds. In this case, a suspend/resume command may be utilized to perform other access operations while an erase operation is performed.